Wireless identification and communication systems are a vital technology in today's world. Most such systems are omnidirectional; their antennas broadcast signals fairly uniformly in all directions. Omnidirectional communication systems are desirable in many applications, because their antennas need not be steered to maintain communication. They can serve broader territories, too.
However, some applications benefit from directional communication systems. Compared to omnidirectional communication systems, directional communication systems use antennas that transmit signals predominantly to, or receive signals predominantly from, a relatively narrow span of directions. Directional communication systems have some distinct advantages. First, since they focus the power they transmit onto a relatively narrow span of directions, they require less power than omnidirectional systems or alternatively are able to transmit farther than omnidirectional systems using the same power. Second, signal interception by an unauthorized third party is less likely, since the third party must be aligned with the transmitting antenna in order to receive the signal.
Secure and reliable wireless communication is particularly important in the context of combat. Often, such communication merely involves identification. Split-second weapon firing decisions are based on target identification. Identifying the target of a weapon that is about to be fired is important to ensure that enemy forces suffer a loss, and not one's own, “friendly” forces. In addition to identifying the target, it should also be determined whether any friendly forces are within a “zone-of-interest” about the target. In the context of weaponry, this “zone-of-interest” is called a “kill zone.” The “kill zone” of a weapon is the space surrounding the target within which the weapon may cause a substantial effect. In the case of lethal weapons, the kill zone is the space within which substantial physical harm, probably death, is likely to occur to a person. Obviously, the size of kill zones varies widely, depending upon the type, configuration and mode of operation of the weapon to which the kill zone corresponds. Knowing that a potential target is not a friendly element, and knowing that no friendly elements are within the kill zone are critically important in order to avoid fratricide (so-called “friendly fire” incidents). Outside of the context of weaponry, a “zone-of-interest” is a space desired to be analyzed or within which warning or identification should take place.
Full communication between elements of a force is also important. However, conventional battlefield communication systems are bulky and thus difficult to transport. Mobility is a key attribute of a modern fighting force. Therefore, a more transportable communication system would be highly advantageous.
Accordingly, what is needed in the art is a system capable of carrying out highly directional electronic identification or warning. More specifically, what is needed in the art is a way to determine whether friendly forces are approaching or within the kill zone of a weapon. Alternatively, what is more specifically needed in the art is a way to warn friendly forces that they are approaching or within the kill zone of a weapon. What is still further needed in the art is a compact, lightweight, energy-efficient system capable of being independent of any host weapon system but compatible with a variety of weapons, including light arms, field artillery, armored vehicles, attack aircraft, bombers, helicopters and combatant ships and non-weapon mobile and stationary platforms, such as tripods.